The invention relates generally to combustion engines, and more particularly, to a system for closed-loop control of combustion in engines, for example, gas engines.
In an engine, for example gas engine, a mixture of gaseous fuel and air are compressed within each of the engine cylinders to create an air-fuel mixture that ignites due to the heat and pressure of compression (self or auto ignition relates to diesel engine) or an ignition source, for example spark plug in gas engines. The air-fuel mixture is exploded via the use of an ignition plug to generate an output power. Unfortunately, engine efficiency, power output, fuel consumption, exhaust emissions, and other operational characteristics are less than ideal. In addition, conventional techniques to improve one operational characteristic often worsen one or more other operational characteristic. For example, attempts to decrease specific fuel consumption often cause increases in various exhaust emissions. Vehicle exhaust emissions include pollutants such as carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter (PM), and smoke generated due to incomplete combustion of fuel within the combustion chamber. The amount of these pollutants varies depending on the fuel-air mixture, compression ratio, injection timing, ambient conditions, engine output power, and so forth.
Engine performance may be improved by controlling combustion within each of the engine cylinders. The factors affecting engine performance may include reduction in coefficient of variance between different cylinders, operating engine closer to knock limits, improved ignition control, changes in gas quality, misfired cylinder, or the like. One or more parameters related to the engine would need to be monitored to control the combustion within each cylinder of the engine. Conventionally, piezoelectric pressure transducers, ion current sensors, or optical detectors are used to monitor one or more parameters related to the engine. However, these conventional sensors are inaccurate, lack in reliability, and are expensive to be used. Another issue with the conventional approach is the requirement of large number of sensors. Hence the complexity of the control system is also increased. Also, none of the conventional approaches provide a feedback of an engine power output to a control system.
There is a need for a suitable control unit that can reliably detect one or more combustion parameters related to an engine and control combustion within each cylinder of the engine so as to improve engine performance.